A sum of money becomes ₹2,000 in 3 years and ₹2,400 in 4 years, at the certain rate of yearly compound interest in case of annual compounding. Find the yearly rate of compound interest.

20% 10% 15% 25%

20%

3rd year                    4th year 2000                          2400 Difference = 400 R% =  \(\frac{400 × 100}{2000}\) = 20%